Carbon brushes are used in electric motors to: ...

Carbon brushes are used in electric motors to: 

(1) Brush off carbon deposit on the commutator (2) Provide a path for flow of current (3) Prevent overheating of armature windings (4) Prevent sparking during commutation
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1 Answer

Answer :

Carbon brushes are used in electric motors to: Provide a path for flow of current.

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Related questions

Which of the following is a characteristic of fractional horsepower repulsion start motors? A. They start with a rotating stator field. B. The short circuiting ring is removed from the commutator while starting. C. The brushes are removed from the commutator while starting. D. They have a low starting torque.

Description : Which of the following is a characteristic of fractional horsepower repulsion start motors? A. They start with a rotating stator field. B. The short circuiting ring is removed from the commutator while ... brushes are removed from the commutator while starting. D. They have a low starting torque.

Last Answer : Answer: B

What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.

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Last Answer : Answer: B

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Description : How many carbon brushes does an electric motor have ?

Last Answer : Electric motor has 1 carbon brush.

State types of enclosures for electric motors.

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Last Answer : Types of enclosures for Electric Motor:  i) Open type enclosure:-  ii) Screen Protected enclosure  iii) Drip proof (moisture) enclosure:  iv) Flame (Fire) proof enclosure:-  v) Totally enclosed type enclosure:-  vi) Pipe ventilated totally enclosed type enclosure:

Suggest electric motors for i) traction ii) crane iii) lathe machine iv) domestic fan.

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Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? A. Higher than normal operating temperature. B. Excessive vibration at normal speed. C. Sparking at the brushes. D. High megger readings.

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The purpose of DC generator brushes is to _____________. A. neutralize armature reaction B. conduct electric current to an outside circuit C. convert DC current to AC current D. provide excitation to a DC generator

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Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature

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The purpose of the commutator and brushes on a DC generator is to _____________. A. transfer generated direct current voltage from the armature to the line B. convert the alternating voltage generated within the armature to a direct voltage C. provide a sliding contact method to excite the field D. reduce sparking between the armature and the carbon brushes

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Description : The current from the stator of an alternator is taken out to the external load circuit through (A) slip rings. (B) commutator segments. (C) solid connections. (D) carbon brushes.

Last Answer : (C) solid connections.

Which of the following brushes can be used for high values of current density ? (a) Metal graphite brushes (b) Hard carbon brushes (c) Electro-graphitic brushes (d) Natural graphite brushes

Description : Which of the following brushes can be used for high values of current density ? (a) Metal graphite brushes (b) Hard carbon brushes (c) Electro-graphitic brushes (d) Natural graphite brushes

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Description : The material for commutator brushes is generally (a) mica (b) copper (c) cast iron (d) carbon

Last Answer : Ans: d

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Description : Brushes of D.C. machines are made of (a) carbon (b) soft copper (c) hard copper (d) all of above

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In a DC motor, it is important to place the brushes along ______

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Last Answer : In a DC motor, it is important to place the brushes along Magnetic Neutral Axis

What are commutator brushes made of?

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How many types of electric motors ?

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Do surplus electric motors normally not work very well?

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Last Answer : Surplus electric motors do usually work very well. I am thinking that you could have accidentally broken it when you bought it. I would bring it back to the store just in case!

Can you still get up and go with electric car motors?

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Universal motors will operate on AC or DC current, and are generally found in _____________. A. portable tools B. large pump motors C. turbo electric main motors D. forced draft fans

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Last Answer : Answer: A

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Last Answer : Answer: C

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